Dalman. S. G. 2012. New Data on Small Theropod Footprints from the Early Jurassic (Hettangian) Hartford Basin of Massachusetts, United States. Bulletin of the Peabody Museum of Natural History 53:333-353. doi:http://www.bioone.org/doi/abs/10.3374/014.053.0201Abstract - A Portland Formation Lower Jurassic (Hettangian) dinosaur tracksite in Granby, Massachusetts, USA, has yielded a diverse dinosaur footprint assemblage. The tracksite preserves 140 theropod dinosaur footprints, ranging in length from 15 to 35 cm; the ichnofauna includes Anchisauripus, Eubrontes, Grallator and other extremely small theropod dinosaur footprints. The small tracks are compared with similar ichnites from the Lower Jurassic of western North America and central Poland. The small theropod footprints, which are described in detail, show some resemblance to the poorly known ichnogenus Stenonyx (Lull, 1904), which is considered an invalid ichnotaxon by many other workers. The footprints exhibit a distinct morphology of the metatarsophalangeal area, suggesting that these small ichnites are closely related to Kayentapus and Grallator. These small tracks are the first reported from the Hartford Basin of Granby, Massachusetts.

In the conclusions section of the recent paper by Kammerer et al., there is a worthwhile discussion regarding the taxonomic assignment of isolated Triassic teeth. In the past some isolated leaf-shaped, denticulated teeth were considered apomorphic and used to erect discrete ornithischian dinosaur taxa (e.g., Hunt and Lucas, 1994; Heckert, 2004). Parker et al. (2005) argued that at least in Revueltosaurus callenderi, the teeth were apomorphic allowing assignment of non-dental material to the taxon. Irmis et al. (2007) discussed this in more detail, arguing the teeth of other purported ornithischians were not assignable to dinosaurs based solely on morphology and in fact could not be assigned to a more inclusive taxonomic level than Archosauromorpha.

However, in this recent paper Kammerer et al. note that many of these Triassic tooth taxa are very similar to the teeth of the traversodontid cynodonts Dadadon isaloi and Arctotraversodon plemmyridon. They especially note that the lower incisors of D. isaloi are very similar to the holotype teeth of Tecovasaurus murryi and the fourth upper incisor of D. isaloi has a similar morphology to Lucianosaurus wildi. Thus the characters that have been used to diagnose at least several of these 'tooth taxa' converge on other forms and are not autapomorphic. Although it would be tempting to use the teeth of Tecovasaurus and Lucianosaurus to suggest the further presence of cynodonts in the Triassic of the American southwest, we cannot discount the similarities of these teeth to archosaurian forms as well and therefore as noted by Kammerer et al., these isolated teeth can presently only be assigned to the level of Amniota rather than Archosauriformes.

Kammerer, C. F., Flynn, J. J., Ranivoharimanana, L., and A. R. Wyss. 2012. Ontogeny in the Malagasy Traversodontid Dadadon isaloi and a Reconsideration of its Phylogenetic Relationships. Fieldiana Life and Earth Sciences 5:112-125. doi: http://www.bioone.org/doi/abs/10.3158/2158-5520-5.1.112Abstract - New craniodental material of the traversodontid Dadadon isaloi from Middle/Upper Triassic basal “Isalo II” beds of southwestern Madagascar is described. These specimens reveal several new autapomorphies of Dadadon, including paired foramina on the frontal near the anterior border of the postorbital and lower incisors with denticulated distal margins. The new material covers a broad size range, providing the first information on ontogeny in Dadadon. Larger (presumably older) specimens of Dadadon isaloi have more postcanine teeth, relatively longer, narrower snouts, and a higher degree of cranial ornamentation than smaller specimens. Postcanine replacement in Dadadon was similar to that of other traversodontids: new teeth erupted at the posterior end of the postcanine tooth row and moved forward. Using information from the new specimens, the position of Dadadon was tested in a new phylogenetic analysis of traversodontids. In the new analysis, Dadadon is strongly supported as a member of a clade also including the South American taxa Massetognathus and Santacruzodon, here named Massetognathinae subfam. nov. This clade is diagnosed by the presence of denticulated lower incisors, relatively small canines, three cusps in the labial margin of the upper postcanines, and low, flat skulls. Massetognathinae is the sister-group of Gomphodontosuchinae, which includes Gomphodontosuchus, Menadon, Protuberum, Exaeretodon, and Scalenodontoides. The Laurasian traversodontids (Arctotraversodon, Boreogomphodon, and Nanogomphodon) form a clade that is the sister-taxon of Massetognathinae + Gomphodontosuchinae. Denticulated incisors evolved multiple times in traversodontid evolution (in massetognathines and Arctotraversodon), and thus this group represents another possibility (besides various archosauromorphs) to be considered when attempting to identify isolated Triassic teeth with denticulated carinae lacking cingula.

Ranivoharimanana, L. 2012. Analyse biomécanique masticatrice chez des traversodontidés eucynodontes du Trias de Madagascar. [Biomechanical analysis of the jaw apparatus in eucynodont traversodontids from the Triassic of Madagascar]. Geodiversitas 34: 505–515. Abstract - Mandible biomechanics analysis cannot take place without the understanding of the development degree and the arrangement pattern of the adductor muscles. In the non mammalian cynodonts, the temporal and the superficial masseter muscles play a primordial role in the lower jaw motion during the food processing. They constitute the key elements of this analysis. Previous studies on non mammalian cynodonts including Dadadon isaloiFlynn, Parrish, Rakotosamimanana, Simpson & Wyss, 1999 and Menadon besairieiFlynn, Parrish, Rakotosamimanana, Simpson & Wyss, 1999 demonstrated the realization, by these animals, of a complex dynamic occlusion of the lower and superior postcanine teeth. The consideration of the bite point as second occlusal fulcrum equal in status to the cranio-mandibular joint is the basis of the bifulcral model. This methodology allows: 1) to quantify the resistance opposed by food at the level of the occlusal site; and 2) to highlight a positive net vertical load, of compressive nature, acting to the level of the cranio-mandibular joint during the interactivity of the elevator muscles, i.e. during mastication.

Abstract - The
Lower Triassic Red Peak Formation of the Chugwater Group has long been
considered to have an extremely poor paleontological record, although the cause
for the apparent dearth of fossils has yet to be been determined. During the
course of fieldwork in central Wyoming numerous vertebrate and invertebrate
ichnogenera (n ≥ 11) were observed. Vertebrate tracks and trackways
representative of dinosauromorph, archosaur, lepidosaur, and testudinate
trackmakers were found (cf. Rotodactylus,
Chirotherium barthii,
Rhynchosauroides,
and cf. Chelonipus
respectively). An invertebrate ichnoassemblage composed of at least 6
ichnogenera consistent with the Scoyenia ichnofacies were also found (e.g., Diplichnites, Lockeia, Fuersichnus communis,
Palaeophycus striatus,
cf. Scoyenia,
and cf. Scolicia).
The majority of these tracks and traces were found in the upper platy facies
(upper 10–20 m of the Red Peak Formation), which is thought to be no younger
than upper Spathian in age. Sedimentary structures, architectural elements, and
lateral stratigraphic relationships support the interpretation of floodplain,
fluvial, and lacustrine deposition for the upper platy facies in central
Wyoming. The Red Peak Formation vertebrate and invertebrate ichnoassemblages,
along with their associated depositional environments, are consistent with a
fluviolacustrine (continental) setting comparable to those described from Lower
to Middle Triassic strata with a Pangean distribution, including the Moenkopi
Formation in the southwestern United States. This ichnoassemblage provides the
first opportunity to observe paleoecological diversity and associated
paleoenvironments within the Lower Triassic of the Chugwater Group.

The New Mexico Museum of Natural History and Science has released a bunch of short, one minute video clips on a variety of fossil animals. I've linked a few of the Triassic-themed ones below. I think this is a great idea.

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About Me

My name is Bill Parker and I am a paleontologist in northeastern Arizona. While my day job mainly involves roaming the badlands of Petrified Forest National Park picking up bit after bit of phytosaur scrap (and finding some good stuff in-between), thus my main focus is the paleontology of the Triassic Period. However, I also have a very strong interest in Civil War history, and am a direct descendent of veterans who fought on both sides. Note: This is a personal site and all posts are my own opinions and do not represent the opinions of the National Park Service.